/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cfft_radix4_init_f32.c
*
* Description:	Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT Initialization function
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
*
* Version 0.0.5  2010/04/26
* 	 incorporated review comments and updated with latest CMSIS layer
*
* Version 0.0.3  2010/03/10
*    Initial version
* -------------------------------------------------------------------- */


#include "arm_math.h"
#include "arm_common_tables.h"

/**
 * @ingroup groupTransforms
 */

/**
 * @addtogroup Radix2_CFFT_CIFFT
 * @{
 */

/**
* @brief  Initialization function for the floating-point CFFT/CIFFT.
* @param[in,out] *S             points to an instance of the floating-point CFFT/CIFFT structure.
* @param[in]     fftLen         length of the FFT.
* @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
* @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value.
*
* \par Description:
* \par
* The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
* Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
* \par
* The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
* Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
* \par
* The parameter <code>fftLen</code>	Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
* \par
* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
*/
arm_status arm_cfft_radix2_init_f32(
    arm_cfft_radix2_instance_f32* S,
    uint16_t fftLen,
    uint8_t ifftFlag,
    uint8_t bitReverseFlag)
{
	/*  Initialise the default arm status */
	arm_status status = ARM_MATH_SUCCESS;

	/*  Initialise the FFT length */
	S->fftLen = fftLen;

	/*  Initialise the Twiddle coefficient pointer */
	S->pTwiddle = (float32_t*) twiddleCoef;

	/*  Initialise the Flag for selection of CFFT or CIFFT */
	S->ifftFlag = ifftFlag;

	/*  Initialise the Flag for calculation Bit reversal or not */
	S->bitReverseFlag = bitReverseFlag;

	/*  Initializations of structure parameters depending on the FFT length */
	switch(S->fftLen) {

		case 4096u:
			/*  Initializations of structure parameters for 4096 point FFT */

			/*  Initialise the twiddle coef modifier value */
			S->twidCoefModifier = 1u;
			/*  Initialise the bit reversal table modifier */
			S->bitRevFactor = 1u;
			/*  Initialise the bit reversal table pointer */
			S->pBitRevTable = (uint16_t*) armBitRevTable;
			/*  Initialise the 1/fftLen Value */
			S->onebyfftLen = 0.000244140625;
			break;

		case 2048u:
			/*  Initializations of structure parameters for 2048 point FFT */

			/*  Initialise the twiddle coef modifier value */
			S->twidCoefModifier = 2u;
			/*  Initialise the bit reversal table modifier */
			S->bitRevFactor = 2u;
			/*  Initialise the bit reversal table pointer */
			S->pBitRevTable = (uint16_t*) & armBitRevTable[1];
			/*  Initialise the 1/fftLen Value */
			S->onebyfftLen = 0.00048828125;
			break;

		case 1024u:
			/*  Initializations of structure parameters for 1024 point FFT */

			/*  Initialise the twiddle coef modifier value */
			S->twidCoefModifier = 4u;
			/*  Initialise the bit reversal table modifier */
			S->bitRevFactor = 4u;
			/*  Initialise the bit reversal table pointer */
			S->pBitRevTable = (uint16_t*) & armBitRevTable[3];
			/*  Initialise the 1/fftLen Value */
			S->onebyfftLen = 0.0009765625f;
			break;

		case 512u:
			/*  Initializations of structure parameters for 512 point FFT */

			/*  Initialise the twiddle coef modifier value */
			S->twidCoefModifier = 8u;
			/*  Initialise the bit reversal table modifier */
			S->bitRevFactor = 8u;
			/*  Initialise the bit reversal table pointer */
			S->pBitRevTable = (uint16_t*) & armBitRevTable[7];
			/*  Initialise the 1/fftLen Value */
			S->onebyfftLen = 0.001953125;
			break;

		case 256u:
			/*  Initializations of structure parameters for 256 point FFT */
			S->twidCoefModifier = 16u;
			S->bitRevFactor = 16u;
			S->pBitRevTable = (uint16_t*) & armBitRevTable[15];
			S->onebyfftLen = 0.00390625f;
			break;

		case 128u:
			/*  Initializations of structure parameters for 128 point FFT */
			S->twidCoefModifier = 32u;
			S->bitRevFactor = 32u;
			S->pBitRevTable = (uint16_t*) & armBitRevTable[31];
			S->onebyfftLen = 0.0078125;
			break;

		case 64u:
			/*  Initializations of structure parameters for 64 point FFT */
			S->twidCoefModifier = 64u;
			S->bitRevFactor = 64u;
			S->pBitRevTable = (uint16_t*) & armBitRevTable[63];
			S->onebyfftLen = 0.015625f;
			break;

		case 32u:
			/*  Initializations of structure parameters for 64 point FFT */
			S->twidCoefModifier = 128u;
			S->bitRevFactor = 128u;
			S->pBitRevTable = (uint16_t*) & armBitRevTable[127];
			S->onebyfftLen = 0.03125;
			break;

		case 16u:
			/*  Initializations of structure parameters for 16 point FFT */
			S->twidCoefModifier = 256u;
			S->bitRevFactor = 256u;
			S->pBitRevTable = (uint16_t*) & armBitRevTable[255];
			S->onebyfftLen = 0.0625f;
			break;


		default:
			/*  Reporting argument error if fftSize is not valid value */
			status = ARM_MATH_ARGUMENT_ERROR;
			break;
	}

	return (status);
}

/**
 * @} end of Radix2_CFFT_CIFFT group
 */
